Power generators typically include a rotating coil in stator coils. The output current of stator coils may be controlled by changing an excitation current flowing through the rotating coil. Some types of power generators, such as alternators, are typically used in applications that include combustion engines, e.g., passenger automobiles, such that the power generator may be connected to the powertrain of the combustion engine.
Power generators can experience degraded performance under harsh environmental conditions, e.g., cold temperatures and lower rotation speeds. Quick speed cycles of an engine, e.g., accelerating and decelerating, may result in a combustion engine periodically operating at lower engine speeds. Further, research efforts for passenger automobiles have increasingly focused on lowering engine speeds in an effort to improve fuel efficiency. Problems associated with operating power generators at lower engine speeds have thus been exacerbated. The performance of power generators in modern fuel-efficient automobiles may be further worsened in colder climates.
Worsened performance of a power generator may result in the generator exceeding the maximum rated output of the generator, or may cause the generator to experience counter-torque from the combustion engine. Such degraded performance can damage the power generator over time.